<template>
  <el-select :value="valueTitle" ref="select" :clearable="clearable" @clear="clearHandle">
    <el-input class="selectInput" :placeholder="placeholder" v-model="filterText">
    </el-input>

    <el-option :value="valueTitle" :label="valueTitle" class="options">
      <el-tree id="tree-option" ref="selectTree" :accordion="accordion" :data="options" :props="props" :node-key="props.value" :default-expanded-keys="defaultExpandedKey" :show-checkbox="showCheckbox" :filter-node-method="filterNode" @node-click="handleNodeClick">
      </el-tree>
    </el-option>
  </el-select>
</template>

<script>
export default {
  name: 'el-tree-select',
  props: {
    /* 配置项 */
    props: {
      type: Object,
      default: () => {
        return {
          value: 'id', // ID字段名
          label: 'title', // 显示名称
          children: 'children' // 子级字段名
        }
      }
    },
    /* 选项列表数据(树形结构的对象数组) */
    options: {
      type: Array,
      default: () => { return [] }
    },
    /* 初始值 */
    value: {
      type: Number,
      default: () => { return null }
    },
    /* 可清空选项 */
    clearable: {
      type: Boolean,
      default: () => { return true }
    },
    /* 是否每次只打开一个同级树节点展开 */
    accordion: {
      type: Boolean,
      default: () => { return false }
    },
    /* 是否开启多选 */
    showCheckbox: {
      type: Boolean,
      default: () => { return false }
    },
    /* 默认展开的节点的 key 的数组 */
    defaultExpandedKeys: {
      type: Array,
      default: () => { return [] }
    },
    placeholder: {
      type: String,
      default: () => { return '检索关键字' }
    }
  },
  data () {
    return {
      filterText: '',
      valueId: this.value, // 初始值
      valueTitle: '',
      defaultExpandedKey: []
    }
  },
  mounted () {
    this.initHandle()
  },
  methods: {
    // 初始化值
    initHandle () {
      console.log('initHandle')
      if (this.valueId && this.$refs.selectTree.children.length > 0) {
        this.valueTitle = this.$refs.selectTree.getNode(this.valueId).data[this.props.label] // 初始化显示
        this.$refs.selectTree.setCurrentKey(this.valueId) // 设置默认选中
        this.defaultExpandedKey = [this.valueId] // 设置默认展开
      }
      this.initScroll()
    },
    // 初始化滚动条
    initScroll () {
      this.$nextTick(() => {
        const scrollWrap = document.querySelectorAll('.el-scrollbar .el-select-dropdown__wrap')[0]
        const scrollBar = document.querySelectorAll('.el-scrollbar .el-scrollbar__bar')
        scrollWrap.style.cssText = 'margin: 0px; max-height: none; overflow: hidden;'
        scrollBar.forEach(ele => {
          ele.style.width = 0;
        })
      })
    },
    // 切换选项
    handleNodeClick (node) {
      this.valueTitle = node[this.props.label]
      this.valueId = node[this.props.value]
      this.$emit('getValue', this.valueId)
      // this.defaultExpandedKey = []
      this.$refs.select.blur();
    },
    // 清除选中
    clearHandle () {
      this.valueTitle = ''
      this.valueId = null
      this.defaultExpandedKey = []
      this.clearSelected()
      this.$emit('getValue', null)
    },
    /* 清空选中样式 */
    clearSelected () {
      const allNode = document.querySelectorAll('#tree-option .el-tree-node')
      allNode.forEach((element) => element.classList.remove('is-current'))
    },
    filterNode (value, data) {
      if (!value) return true;
      return data.name.indexOf(value) !== -1;
    }
  },
  watch: {
    value () {
      this.valueId = this.value
      this.initHandle()
    },
    filterText (val) {
      this.$refs.selectTree.filter(val);
    }
  }
};
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
.el-scrollbar .el-scrollbar__view .el-select-dropdown__item {
  height: auto;
  max-height: 274px;
  padding: 0;
  overflow: hidden;
  overflow-y: auto;
}
.el-select-dropdown__item.selected {
  font-weight: normal;
}
ul li >>> .el-tree .el-tree-node__content {
  height: auto;
  padding: 0 20px;
}
.el-tree-node__label {
  font-weight: normal;
}
.el-tree >>> .is-current .el-tree-node__label {
  color: #409eff;
  font-weight: 700;
}
.el-tree >>> .is-current .el-tree-node__children .el-tree-node__label {
  color: #606266;
  font-weight: normal;
}
.selectInput {
  padding: 0 5px;
  box-sizing: border-box;
}
/* 开发禁用 */
/* .el-tree-node:focus>.el-tree-node__content{
    background-color:transparent;
    background-color: #f5f7fa;
    color: #c0c4cc;
    cursor: not-allowed;
  }
  .el-tree-node__content:hover{
    background-color: #f5f7fa;
  } */
</style>
